Defining the functional role of a novel MS susceptibility gene, IL7R alpha chain. Multiple sclerosis (MS) is a debilitating neurodegenerative disorder of the central nervous system (CNS) that is thought to be mediated by T-cell autoimmunity and causes neurological inflammation and progressive neurological dysfunction. The `complex disease' nature of MS has made it difficult to identify genes implicated in, and understand the underlying molecular mechanisms of the disease. We have recently generated exciting new data which has identified significant association with MS of a SNP within the interleukin 7 alpha chain receptor gene (IL7R1). Further, we have proven that the associated SNP leads to increased skipping of the transmembrane domain of the protein, resulting in increased production of the soluble form of IL7R1. The objective of this grant is to build upon this ground breaking discovery. We propose to identify the cis- and trans- factors involved in exon 6 IL-7R1 splicing, determine the effect that exon skipping has upon interleukin 7 (IL-7) and thymic stromal lymphopoietin (TSLP) pathways, and the influences that this has upon naove T- cell differentiation and memory T-cell homeostasis. By elucidating these mechanisms we hope to gain a better understand IL7R1 is functionally implicated in the etiology of MS.